JZTRAC - print processor trace-back

This routine is called from ZPOSTM during error termination.

CALL JZTRAC (MODE)

It prints the processor names and the call-bank addresses, it also optionally marks some banks as ``critical'' to get a full dump of these banks in DZSNAP. Marking ``critical'' depends on single bits in MODE:

    bit 1  all SV banks in the chain
        2  all call banks in the chain
        3  all banks pointed to from the links
           in the current call banks at LQUP and LQDW.